Piston ring



May 15, 1928.

D. M. SOLENBERGEYR PISTON RING Filed April 9, 1924 Patented Mayv 1.92.8.'-

U-NiTED sra Y. 71,670,082. rEs i PAT-ENT" Jonica.'

DEAN 1L soLENBEnGER,-` or CLEVELAND, omo, AssIGNon To '.rnE s mPLEx `mamon RINGCOMPANY or omo.

Application mea Aprii 9,

vThis'inventionrelates to piston rings such as are used for'sealing the intervening space tion Serial No. r632,290 filed April 16, 1922.

I have found that in order to provide a. perfect seal between the piston and cylinder wall, the sealing ring must be free to move c lradially within the ring groove in'the piston,

and 'such freedom of movement must besuficient to permit the ringto' conform to the cylinder wall atall engine speeds. Due to the fact that an internal combustion engine often operates at very highy speeds, and on the upstroke the piston tends to bear on one side of the cylinder wall witha greater force than on the other, and vice versa on the down stroke, it willbe readily apparent thatl the time element for this radial movement or breathing og ther ring within thering groove is exceedlngly small and must be almost instantaneous. In cases where the cylinder has been worn out ofround, this radial movement of'the ring is .of course more pronounced than. withl substantially round cylinders and pistons, but in any event a certain degree of movement is necessary due to the lateral thrust ofthe piston in opposite directions on the `up 'and down strok If the ordinary ring is made' with sufficient clearance in width to permit, to a certain degree, this instantaneous radial movement,

' then the ring moves back and forth in a longitudinal direction within the ringgroove on the'up and down stroke ofthe piston. The exceedinglyA small longitudinal motion at first is of little consequence but this cons tant hammering soon widens the ring groove to an; appreciable `extent and the longitudinalmovement of the ring Within the groove then causes thc'ring to function asa pump with the result that 'the spark fplugs are soon fouled with o'i'l and the combustion chamber filled withcarbon. It has been the general practiceheretfore to overcome the above diiculties'by fitting the ring very accurately to'the ringv groove' and then placing a spring expander between the sealing ring and, piston and while in some cases this arrangement tends to correct the trouble to 'some extent, the

PIs'ToN RING.

V1924. serial No. 705,112.

result is farfrom being entirely satisfactory. The chief reason forfailure o this arrangement is due to the aforementioned widening of the ring groove and also to the-fact that there is not sucient space between the sealing ring and piston to place an expander of sucient size to exert a radial force great enough on tthe present day piston ring to cause said ring tov conform instantaneouslyl to the cylinder wall.

AMEnIcA, INC., yor CLEVELAND, omo, A conroRATIoN og-x' It is the gegeral object of the present illvention to provide an exceedingly Hexible sealing rlng so that the same 'may conform` instantaneously with the cylinderwall Aand be effective even ^at high engine. speeds, in

providing a perfect seal between -the piston 1 and cylinder wall.v

Another 'object is to provide aring of this:`

character which shall be compressible longitudinally and hence automatically take' up any wear-or irregularities `in the ring groove and thereby prevent oil pumping due" to' longitudinal movement of the ringf within the ring groove. ."Anotherobject is to providea ring of the aforesaid character which shallbe tively thin in depth so as to be exceedingly flexible and permit the ring to readily conform to out of round' cylinders and also to provide sufficient space between the ring and sfo rela'- piston to insert, when desired, an expander ofsufcient size to exert the necessary force to produce the aforementioned instantaneous radial movement of the ringwithin-the ring groove.

A still further object is to yprovidea seal-"- ing ring of this general character-which shall be simple in construction, 'inexpensive to manufacture, easy to install, and highly eff i fic'ient in operation.`

With these and other objects in view, th e` invention consists in the` various novel features of construction and arrangement or combination, all of which will be fully described hereinafter and appended claims. v.

In the dra-wing accompanyin and form-V ing part of this application, ig. -1 is a pointed out in the side elevation of a rlng constructed in ac cordance with my invention; Fig. 2-is a frag-' mentary vertical sectional View th'rou h a piston and cylinder showing thepiston tted with la standard ring and -two rings constructed in accordance with my' invention; Fig. 3 is a plan viewvof my ring showing lower spaced over erably so arranged that the circumferential.

vplurality ofcircumferential 'grooves 3 for the reception of the sealing rings. One or more of these rings' are constructed in a0.-v

cordance with my invention and preferably similar to that shown particularly in Iig. 1, wherein 4 denotes the sealing ring which is provided with a lurality of upper and apping circumferential slots 5. These slots are preferably so' arranged that they deine outer bars 6 and central bars 7, said outer bars beingI connected at spaced intervals by solid portions 8 to the central bars. This arrangement permits the ring: to be compressedlongitudinally at all points so groove, lthe ring will automatically exert a slight pressure against the side edges of the ring groove and accommodate itself evenly to ring grooves which are worn or of slightly varying widths.

It will be noted that outer bars are of greater width thanl the center bars. By varying the length, breadth and thickness ofthe center bars I am enabled to control the longitudinal pressure exerted by the ing against the side edges of the ring groove. A relatively thin 'center bar as shown ermits me to obtain a relatively low longitu inal pressure as will beiexplainefl more fully hereinafter. Also it will be noted that by providing relatively wide outer bars, the danger of breakage due to handling of the ring when installing the same, is reduced to a minimum.

The stepped joint indicated at 10 is prefline of overlap of the tongues is to one side of the circumferential axis of the ring so as to provide strong and durable tongues 11. The' joint as a whole is rendered flexible by continuing one of In actual practice I have'discovered that the entire success of a ring of this general character is dependent upon two factors concerning the generalv proportions of the ring and the resultant pressures exerted by said,

ring. First, and most important, I have found that the longitudinal pressure of the ring when compressed to the width of the ring groove, must be verylew in order to permit the aforementioned free radial movement of the ring. .A ring cnstructed to 'have this suiiciently low pressure longitudinally, may be shownA by mathematics to have insuiiicient pressure to withstand collapse due to the force of the explosion and also to the inertia of the unsupported portions of the ring when the piston reaches the end that when inserted in a ring.

the slots 5 across the joint.

of its stroke and is starting in an opposite direction. By unsupported portions of the ring, I means those portions which are free to move due to their inertia, whenthe piston reaches the end of its stroke. As an example consider the ring shown in Fig. 1 fitted to a piston movingupwardly. At the upper end of the stroke the inertia of the ring will cause upper bars 6 to bear tightly against'the upper side edge of the ring groove and be supported thereby. The lowerbars 6 and solid portions 8 connecting the lower bars to the central bars 7 together with substantially one half the mass of the central bars are 'unsupported and tend to move toward the wall of ring groove and vice versa on the down stroke of the piston. If this actually happened, it would be obvious that the seal would be broken and the ring would fail to function properly. It would thus seem that a paradox has been reached. However, I have found through a lar e number of successful experiments the ighly important fact that a ring constructed to have insuii# cient longitudinal pressure against the sides of the ring groove to prevent collapse due to the explosiony and alsoto the inertia of the unsupported portions of the ring, does not.

.collapse in. actual practice,land the ring still maintains suiicient pressure against the sides of the ring groove to efectually seal the piston at these surfaces'. lapse may be due to the oil filling the slots in the ring and also the ring groove and thereby supporting the ring during the instant the excessive pressures are applied. The low Vlongitudinal pressure of the ring thus obtained is within such limits as to permit free radial movement of the ring'and hence a perfect seal isv obtained between the ring and cylinder wall.

As an example of one of my experiments I might state that an automobile motor fitted with a slotted ring of the general character of that shown in Fig. 1, but having alongitudinal pressure of 10 lbs. when compressed to the width of the ring groove which pressure was slightly greater than the inertia value of the unsupported portions, operatedl more or less satisfactorily when the car was driven .at low speeds, but when driven at 25 miles per hour or over, the exhaust smoked badly and the firing chamber became fouled with oil. This fouling of the firing chamber was due to the inability of the ring to move freely in a radial direction at medium to high speeds. A new i 4 ring of the same general character as before sence of oil.

but having a lon itudinal pressure of 5 lbs.,

which was materially less than the theoretical collapse value, was placed in the ca r and the previous failure immediatel turned to success as the exhaust showed c ear at even the maximum speed and the firing chamber and Aassociated parts showed anentire ab- The compression was greatly increased and the consumption of oil reduced to a minimum;

' In general I have found that a longitudinal pressure having a ratio of between zero and substantially 2% lbs. perV inch of diam-r eter of the ring will prove satisfactory or in other words that a ring constructed to have a longitudinal pressure (when compressed to the size of the ring groove) 'which is less than the theoretical collapse value at maxigether with its mum speed will prove successful. It will be understood that the term vmaximum speed is 4used 'in the specification and claims to vmean the theoretical speed atwhich the motor develops maximum horsepower.

In new or comparatively new motors Fig. 1 and having the usual depth of the standard ring as indicated at 4a in Fig. 2.

The second feature of my ring consists in making the depth of the ring within certain limits when it is to be used for worn or out of vround cylinders, so that' the ring will be extremely flexible in accommodating itself readily to the cylinder wall and also providing suicient space between the ring and the bottom or inner wall ofthe standard ring groove to permit an expander to be inserted therein to assist; the ring in conforming to the cylinder wall. By referring to Fig. 2. it, will be noted that I have shown one of my -improved rings in the upper groove and a standard ring 12 in the lower groove. It will be lat once apparent that my ring is materially less in depth rthan'the standard ring. The depth of standard rings varies between 31/% to 5% of the diameter of the ring while I preferably make my ring so that the depth 'thereof is less than 3% of the diameter. The small depth of the ring toy peculiar slotted construction provides a maximum flexibility so that the ring may be readily distorted to any desired I which are adapted to contact with thering shape. In order to assist the ring in con-v forming to out of round cylinders I preferably place an expander 14 back of the ring as shown in Figs. 3 and '4. This expander is formed from a resilient; metal such as spring steel and is provided with an undulating circumferential contour. The surfaces 15 are arcuate so as to provide a maximum area of contact therewith, andthe portions 16 lying intermediate these arcuate surfaces arev formed with substantially the same radius as the aforementioned arcuate portions but'are.

disposed in an opposite direction. The porv tions 17 connecting the oppositely disposed Aarcuate surfaces are substantially straight.

An'expander thus formed provides, maximum area of contact between the piston and1 and the combination of my ring and e`xpander provides a perfect seal between the` piston and cylinder for new motors or for motors whose cyliders are badly wornout of round. In fact, numerous m'tors, wherein' the Wear had been so great that regrinding ofthe cylinders seemed the only remedy,

have been fitted with my rings and expander and the resultl produced is egual in every Instance to afregrin'ding job an at .afrac'tion of the cost thereof. wherein the cylinders are substantially l round, I use a ring similar to that shown in Having thus described my invention, what I claim is 1. The lcombination with a cylinder and an annularly grooved piston therein. of f a single piece axiallyaexpansible split ring in said groove, said ring being limited in radial thickness for extreme flexibility and of itself exerting a radial tension less than required for maintaining sealing contact with the cyl-y inder, and a corrugated ribbon expander in said groovep'for exerting a distributed radial pressure on said ring suiiicient to conform the same to thesurfaceof a distorted cylinder and to'maintain sealing Contact there? with, said pressure being independent of any axial pressure of said ring against a side wall of'said groove. v

2. The combination with'a cylinder and an annularly grooved piston therein` of a single piece ,circumferentially slotted split ring in said groove, said ring being of a normal width greater than the groove to exert a predetermined axial tension on the side wall of the groove and being also limited in radial thickness for extreme flexibility and of itself exerting a radial tension less than required for maintaining sealing contact witlLsaid cylinder, and a corrugated I ribbon expander in said groove for exerting a distributed radial pressure on said ring suilicient to conform the same to the surface of a distorted cylinder and tomaintain sealing contact therewith, said pressure being independent of the axialpress'ure of said ring against the side Wall of said groove. y

3. The combinaton with an annularly' grooved member, 'of a single piecering-in said groove circumferentially slotted to iml part axial resiliency thereto; and a .corrugated ribbon expander in -said groove bearing against thevbottomV thereof and' against said ring to exert a distributed radial pressure which `is sufficient to overcome the frlctional resistance due to the axial pressure.

4. The combination with an annularly grooved member, of a single piece ring in said groove circumferentially slotted to impart axial resiliency thereto and to exert a predetermined pressure on the side Walls thereof sufficient to maintain a seal under working conditions, and resilient means reacting on said ring and groovedmember for exerting a distributed radial pressure thereonthat is sutlici'ent to overcome the frictional resistance due to said axial pressure.y

5. The combination with relatively reciprocating members having clearance therebetween, one of said members having an annular groove therein,` of a single piece ring Within said groove resiliently axially expansible to exert a predetermined pressure against the side walls thereof sufficient to maintain a seal under working conditions,

said ring being also movable radially in said ciprocating members having clearance there tween, one of said members having an annular groove therein, of a single piece ring Within saidl groove resiliently axially expansible to exert a predetermined pressure against the side Walls thereof, said ring being also movable radially in said groove during reciprocation` and means for applying a distributed radial pressure between said ring and grooved member sufficiently in excess of said axial pressure to overcome the frictional resistance to said radial movement of the ring in said groove and also resisting lateral displacement of said grooved member during reciprocation to assist in holding the same from slap against the cooperating member.

7. The combination, with a reciprocating member having a groove, of a one piece circumferentially slotted split piston ring in said groove, said slots being so arranged as to provide a longitudinally yieldable ring capable of exerting a slight pressure against the side walls of the ring groove, the said ring having a depth not exceeding three percent of its diameter'thereby to provide fie'xibility in a radial direction, and an expansion ring interposedl between said piston ring and the inner wall of said groove.

The combination with a split ring hav- 8. ing lubricant passagesA extending therethrough, and arranged in circumferential series, of relativelyV reciprocating members one of which is provided with an annular groove for receivlng said ring and forming an otherwise substantially closed lubricant retaining channel and means for dividing the annular oil space within said ring groove into separate compartments. 9. Thetcombination with a split ring having lubricant passages extending therethrough arranged in circumferential series, of relatively reciprocating members one of which is provided with an annular groove for receiving said ring and forming an otherwise,substantially closed lubricant containing channel, .a corrugated ribbon expander in said groove bearing against said ring and the bottom of the groove and d1- viding the annularrspace into a series of separate compartments.

10. The "combination with an annularly grooved member, of a single piece ring in said groove resiliently axially expansible to maintain a sealing contact With the side walls thereof and provided with lubricant passages extending' therethrough arranged in circumferential series, and a. corrugated ribbon expander within said groove bearing against said ring and the bottom of the groove to form a distributed radial pressure and dividing the annular space within the groove into separate compartments.

11. In an internal combustion engine, the

combination with a. ymember having an annular groove therein of a single piece trans-` split ring fitting Within said groove and limited in radial thickness to impart a relatively high degree of flexibility for conforming to a non-circular or distorted cylinder and a corrugated ribbon expander seated on the bottom lof the groove and exerting a distributed radial pressure on said ring.

12. In an internal combustion engine, the combination with a. member having an annular groove therein, of a single piece transsplit ring fitting -Within said groove an'd limited in radial thickness to less than three and one-half per cent of the diameter to ilnpart a relatively high degree of flexibility thereto for conforming to a non-circular or distorted cylinder and a corrugated ribbon expander seated on the bottom of the groove and exerting a 'distributed radial pressure on said ring.l

- 13. Inan internal combustion engine, .the

exerting a distributed radial pressure on` said ring'for conforming the same to a noncircular or distorted cylinder.

14. an internal combustlon engine, the combination with amember having a ring groove therein, of asingle piece trans-split ringin said groove reduced in radial depth to impart a relatively high degree of lexibility thereto for conforming to a noncir 'cular or distorted cylinder, said ring bein provided with circumferentially distribute oil passages therethrough and a corrugated ribbon expander located between said ring and the inner Wall of the groove.

15. In an internal combustion engine, the combination with av member having a ring groove therein, of a single piece trans-split ring in said groove circumferentially slotted to form oil passages therethrough and being reduced in radial thickness to impart a relatively high degree of flexibility thereto forconforming to a non-circular or distorted cylinder and a corrugated ribbon expander located between said ring and the inner wall of the groove.

16. In an internal combustion engine, the combination with a member having a ring groove therein, a single piece trans-split ring in said groove having parallel series of circumferential slots therethrough, said ring being limited in radial depth to impart a relatively high degree of flexibility thereto for conforming to a non-circular or distorted cylinder, and a corrugated ribbon expander between said ring and .thev inner wall of the groove.

In .testimony whereof I hereunto aiix my signature.

DEAN M. SOLENBERGER. 

